Improvement in pendulum-levels



A. C. L. DELSARTE. Pendlum Levels. N0. 142,005, V PatehtedAugustl9vJ873.

ADRIEN CHARLES LOUIS DELSABTE, OF PARIS, FRANCE.

IMPROVEM'ENT IN `PENDULUMLEVELS.

Specification forming part oi Letters Patent No. 142,005, dated August19, 1873 vapplication,filed August 31, 1872.

To all whom it may concern:

Be it known that I, ADRIEN CHARLES Louis DELSARTE, of Paris, in theRepublic ofFrance, have invented certain Improvements inPendulum-Levels, of which the following is a speciiication: s

In the hitherto-known pendulum-levels the index or hand for indicatingon a dial-plate or graduated limb the variations in level forms animmediate part of the pendulum -'rod, in consequence of which, if ashort rod be made use of, the indications on the limb do not with a rodof comparatively very small length,

which, consequently, permits of reducing the levelto a very smallcompass. For this purpose I interpose between the pendulum-rod andtheindex a pinion and wheel; or, if wished, two or more sets of suchgearing, by which means the sensibility of the level may, consequently,be increased to any required extent, though the pendulum-rod be'of acomparatively very small length; and I further make use, in combinationwith the said gearing, of an arrangement for causing the indentations orteeth of4 the gearing to constantly fully engage into each other, and bythus exerting their full eifect insure the accuracy of the indicationsof the indexr v In the annexed drawing, Figure l shows a full size frontelevation view of my improved pendulum-level; Whereas the Figs. 2 and 3represent, on a scale double that of Fig. I, respectively, a side and aback elevation view of the mechanical parts of the level, the dialplateand the pinion being in Fig. 2 represented as partly cut away and somevother parts shown in vertical section, while lin Fig. 3 only part ofthe teeth of the wheel which drives the pinion are represented.

In these three figures the same letters refer to corresponding parts.

The dial-plate A, and mechanical parts connected thereto, are xcd in aframe, (l, the four sides c1 c2 o3 c4 of which require to be situatedexactly at right angle to each other, and those, c1 and c3, at rightangle with the zero of the dialplate. The spindle or axis m of the handor index B carries a pinion, i, of such length as to allow the twotoothed spur-wheels D and D of acting simultaneously on the indentationsof the said pinion, these wheels D and D being situated parallel to eachother on the same spindle a, and of exactly the same size andindentations,the number of teeth of these wheels and of the piniondepending on the speed to be given to the index B. The pivoted ends ofthe spindles m and n turn in the dial-plate A and in a potance orbridge, Gr. The wheel D is iixed, and the other, D', tted loose, on thespindle n, and this latter wheel, D, is provided with ay counterweight,d', by the effect of which the wheel D will constantly exert a kind ofleverage on the pinion r, and cause the tooth of this latter, which, atthe time being, is in gear with one of the teeth of the wheel D, to beacted upon to the full extent of its power by the said tooth of thewheel D, by which means Vthe accuracy of the indications of the index Bwill be insured. The pendulum-rod j' is very short, and provided at itslower end with a comparatively very heavy bob or weight, F, whereas atits upper end the said rod is fixed to a forked piece, H, which mayswing freely on a pin, t',

inserted in the hub or socket J, by which the Y wheel D is fixed t0 thespindle a.

In small instruments in which gearing is made use of if the teeth arenot mathematically true-t'. e., if their curved ends are not perfectlyepicycloidal-which in practice, and

particularly in cheap-instruments, is seldom Y the case, there alwaysexists a twofold action` the index carried by the pinion iscomparatively long. In this invention the counterweighted loose Wheel Dforces the tooth of the pinion, which for the time being is engaged withthe wheel, to come and remain in contact with the corresponding tooth ofthe driving-Wheel, Whatever may be the shape of the curved part of theteeth.

The counterweighted loose Wheel is found preferable to a hair-spring,because a spring will make a series of extensions and contractionsbefore actually coming to rest.

The manner of making use of my improved pendulum-level is exactly thesame as for other instruments of the same class, any de- Witnesses:

ABRAHAM GERARD BRADE, JEAN BAPTISTE STIRNLING.

